1. Field of the Invention
The present invention relates to a technique for adding to a tracking controller an eccentricity compensation control signal according to an eccentricity amount and angular velocity of an optical disc and for improving accuracy of a tracking pull-in in an optical disc drive apparatus, particularly, in a previous stage of the tracking pull-in.
2. Description of the Related Art
Accuracy of tracking pull-in is caused by a period of a track zero crossing signal due to an eccentricity amount of an optical disc. Since a response band of a tracking control has a finite value, the tracking pull-in is started at a track zero crossing position at which a track zero crossing period is maximized. After the tracking pull-in, a rotation frequency component and amplitude component of the optical disc contained in a tracking control signal are extracted and the extracted components are added as a feed-forward to the tracking control signal. Thereby, a steady tracking error can be reduced and tracking accuracy can be improved. The above is described in Japanese Unexamined Patent Application Publication No. Hei 10-21571.